Wool processing

Combing

Wool is combed in order to:

• straighten up the fibres;
• lay the fibres parallel;
• remove tangles (neps);
• remove short fibres; and,
• remove vegetable matter.

The most commonly used comb is the Schlumberger or rectilinear comb – also known as the French comb, continental comb or dry comb. While this (and other combs) are complex machines, what they do is fairly simple.

The comb has a rotating cylinder that has a section with fine pins set very close together – approximately 25 per centimetre. Slivers of wool are fed into the comb through a gill box and hung across a plate above the comb. The slivers are clamped down firmly, and the cylinder rotates, bringing the comb around to comb the loose ends of the over–hanging fringe.

A drawing-off roller unit then comes across to grab onto the combed ends and draw them through an intersect comb. The combed wool is then reconstituted back into a special sliver called a top, which is fed into another can.

While this is happening, the comb section keeps rotating around to a small brush, called a noil brush, that brushes the short bits of fibre (i.e. noils) held in the comb into another can under the machine. If there was vegetable matter in the wool, this will have been combed out of the wool and will be brushed off the comb section along with the noils.

Noils are generally re-used in woollen yarn manufacture, where fibre length is not so critical.

Tops are often traded as a separate product. They have to go through at least one more step – reducing or drawing before being spun into yarn.